Can't create handler inside thread that has not called Looper.prepare()

android_error.java

JAVA

new Handler(Looper.getMainLooper()).post(new Runnable() {
    @Override
    public void run() {
        Toast toast = Toast.makeText(mContext, "Something", Toast.LENGTH_SHORT);
        toast.show();
    }
});

KOTLIN

Handler(Looper.getMainLooper()).post {
        Toast.makeText(mContext, "Something", Toast.LENGTH_SHORT).show()
}